The proxy in buildExpectation() returned FluentRelation raw (not
proxied), so .and/.or chaining happened outside the assertion store.
The second relation was never stored — checkAll() only evaluated
the first relation (false positive).
Add ensureAndOrProxied() to override .and/.or on FluentRelation
instances so compound builders flow through the assertion store
proxy. Preserves instanceof FluentRelation checks (no JS Proxy on
the instance, just property overrides).
3 regression tests cover .and, .or, and triple-chaining.
John Dvorak
771ddaea4e